East Pacific/2015/01C/Archive/2
Public advisory TROPICAL DEPRESSION ONE-C PUBLIC ADVISORY NUMBER 2 WIKI-HURRICANES FORECASTING CENTER 11:00 AM HST TUE JUL 7 2015 ...DEPRESSION ORGANIZING SLOWLY IN THE CENTRAL PACIFIC... SUMMARY OF 11:00 AM HST... 21:00 UTC... INFORMATION --------------------------------------------------- LOCATION...8.1N 166.7W CENTER POSITION CONFIDENCE: FAIR... ± 30 MI... 50 KM ABOUT 1,085 MI...1,745 KM SW OF HONOLULU, HAWAII MAXIMUM SUSTAINED WINDS...30 KT...35 MPH...55 KM/H MINIMUM BAROMETRIC PRESSURE...1005 MB...29.68 INCHES PRESENT MOVEMENT...NW AT 3 KT...3 MPH...5 KM/H DISCUSSION AND 48-HOUR OUTLOOK --------------------------------------------- At 11:00 am HST, the center of Tropical Depression One-C was located with fair confidence near 8.1N, 166.7W, about 1,085 miles (1,745 km) southwest of Honolulu, Hawaii. Maximum sustained winds were 30 knots (35 mph, 55 km/h), the minimum barometric pressure was 1005 millibars (29.68 inHg), and the cyclone was moving northwest at 3 knots (3 mph, 5 km/h). Environmental conditions are expected to be generally conducive for slow development over the next 48 hours. NEXT ADVISORY ------------------- Next complete advisory at 6:00 pm HST. $$ Forecaster TheAustinMan Discussion TROPICAL DEPRESSION ONE-C DISCUSSION NUMBER 2 WIKI-HURRICANES FORECASTING CENTER 11:00 AM HST TUE JUL 7 2015 Tropical Depression One-C has become a little bit better organized since the first advisory, wwith shower activity now progressing atop the northern semicircle of the circulation. However, convection has warmed and dropped considerably since six hours ago, as the large band of thunderstorms that existed to the south of the storm have transitioned into weak banding features around the southeastern and northeast quadrants. Convection about the center also remains loose at this time, with isolated cells developing in rather scattershot fashion. Microwave imagery from 1850z depicts a defined circulation and primitive banding but otherwise disorganized convection. While a RapidScat pass at around 1512z this morning revealed a swath of 30-35 knot conditions, these were located near an International Space Station altitude change trajectory and were also associated with convection which has diminished since then. Thus, the intensity has been kept at 30 knots, making One-C a tropical depression. One-C has been travelling quite slowly this morning due to the weak steering currents it currently lies within. Currently, the dominant steering force appears to be a mid-level disturbance centered northeast of the Hawaiian islands, which is helping to induce a weakness in the subtropical ridge, causing One-C to track northwestward. As this disturbance moves westward, the subtropical ridge should restrengthen and override the northwesterly motion, inducing a more westerly motion after about two days and through the end of the WHFC forecast range. Currently the computer models follow this general forecast idea, but a large spread nonetheless exists, with the BAMD only rising as far north as 11N while the CMC takes One-C as high as 15N. Since the general steering parameters forecast have not changed, the WHFC track this advisory is an update of the last. Environmental conditions remain conducive for development as One-C tracks towards the northwest and then west-northwest, with the SHIPS indicating that the 15 knots of shear One-C is currently in will be the maxima over the next five days as shear is expected to steadily decrease. The upper-level environment is expected to be generally favorable, and warm waters with conducive sea surface temperatures should provide the energy for One-C to tap into as it intensifies. Currently, storm forecast models are much more aggressive with One-C than global models, with the LGEM and SHIPS indicating steady intensification through the forecast period with LGEM at 92 knots and SHIP at 75 knots at 120 hours. Global models are less optimistic, with the GFS and its ensembles remaining rather stagnant through 5 days, in addition to the CMC and ECMWF. Given the generally favorable conditions, however, the WHFC intensity forecast remains weighted towards the local models and indicates a stronger storm. INIT 07/2100Z 8.1N 166.7W 30 KT 35 MPH 12H 08/0600Z 8.8N 167.3W 30 KT 35 MPH 24H 08/1800Z 9.2N 167.7W 35 KT 40 MPH 36H 09/0600Z 10.1N 168.6W 40 KT 45 MPH 48H 09/1800Z 10.4N 169.5W 45 KT 50 MPH 72H 10/1800Z 10.9N 171.3W 50 KT 60 MPH 96H 11/1800Z 12.0N 174.0W 55 KT 65 MPH 120H 12/1800Z 13.6N 177.8W 65 KT 75 MPH $$ Forecaster TheAustinMan